Living Safely: Low Road Mortality in Squamates near Burgas, Bulgaria

The study represents the results of a long-term (2016 to 2021) survey on the herpetofauna inhabiting the vicinity of a heavily loaded section of the road E 87. The investigated road splits a Protected site from the net NATURA 2000 BG0000271 “Mandra-Poda”. The Protected site is known for its high biodiversity and its dense populations of vertebrates, which thrive in the area. Directly near the inspected road and on the pavement, we were able to detect five species of snakes, three species of turtles and two species of lizards. Among the squamates, rare observations were made of the European nose-horned viper (Vipera ammodytes), detected twice, and the European glass lizard (Pseudopus apodus), detected three times. Three other species—the Bloched snake (Elaphe sauromates), the Caspian whipsnake (Dolichophis caspius) and the Rhodos green lizard (Lacerta dyplochondrodes)—were found in larger numbers during some of the field surveys and here we provide information concerning the hot moments of their activity in the vicinity of the road. The Grass snakes (Natrix natrix) and the Dice snakes (N. tessellata) formed dense groups in the direct vicinity (closer than one and half meters) of the investigated road section. Despite the high number of recorded snakes and lizards, only isolated cases of vehicle collisions were observed. We suggest that the local squamate population had developed a complex of ethological specifics related to feeding, basking, shading, and copulation, which helped them to benefit from the road and avoid the risks related to the heavy traffic.